low power version (integrates commits of @scott-42)

Firmware/cuff.asm

@@ -7,58 +7,114 @@
 .cseg
 
 .org 0x0000
-rjmp RESET
+	rjmp RESET
+.org 0x0008
+	rjmp WDT
 
-.def temp = R16 ; general purpose temp
-.def idx = R17 ; sine table indexer
-.def delaycnt1 = R18 ; counter for 1ms delay loop
-.def delayms = R19 ; keeps track of how many ms left in delay
+.def temp = R16			; general purpose temp
+.def idx = R17			; sine table indexer
+.def delaycnt1 = R18		; counter for 1ms delay loop
+.def delayms = R19		; keeps track of how many ms left in delay
 
 RESET:
-sbi DDRB, LED ; LED output
-sbi PORTB, LED ; LED off
+	sbi DDRB, LED ; LED output
+	sbi PORTB, LED ; LED off
+
+	; setting all pullups on unused pins (for power savings)
+	; would having them all be outputs use less power?
+	ldi temp, (1<<PUEB3)|(1<<PUEB2)|(1<<PUEB1)
+	out PUEB, temp
+
+	; changing clock prescale to slow down the processing power 
+	; (for power savings)
+	ldi temp, 0xD8 ; write signature
+	out CCP, temp
+	; scale to divide by 256. So 8Mhz -> 312.5KHz
+	ldi temp, (1<<CLKPS3)|(0<<CLKPS2)|(0<<CLKPS1)|(0<<CLKPS0) 
+	out CLKPSR, temp
+	
+	; set up fast PWM output timer WGM[3:0] = 0101
+	; COM0A1 = 1, COM0A0 = 0 or 1
+	ldi temp, 0xC1			; Fast PWM (PB2 output)
+	out TCCR0A, temp
+	ldi temp, 0x81			; fastest clock
+	out TCCR0B, temp
+
+	; we dont use the top of the counter since its only 8 bit
+	ldi temp, 0
+	out OCR0AH, temp
+
+	; setup watchdog
+	ldi temp, 0xD8		; write signature
+	out CCP, temp
+	; set watchdog in interrupt mode and 4k cycles
+	ldi temp, (0<<WDE)|(1<<WDIE)|(1<<WDP0) 
+	out WDTCSR, temp
+
+	; enable sleep mode
+	ldi temp, (1<<SE) ; by default the mode is 000 Idle
+	out SMCR, temp
+
+	sei ; enable global interrupts
+	
+	ldi idx, 0
+LOOP:
+	; This is start of Code in Tiny10 (0x4000)
+	ldi ZH,	high(SINETAB*2) + 0x40 
+	ldi ZL, low (SINETAB*2) ; init Z-pointer to storage bytes
 
-; set up fast PWM output timer WGM[3:0] = 0101
-; COM0A1 = 1, COM0A0 = 0 or 1
-ldi temp, 0xC1 ; Fast PWM (PB2 output)
-out TCCR0A, temp
-ldi temp, 0x81 ; fastest clock
-out TCCR0B, temp
+	add ZL, idx
+	inc idx
 
-; we dont use the top of the counter since its only 8 bit
-ldi temp, 0
-out OCR0AH, temp
+	ld temp, Z ; load next led brightness
+	cpi temp, 0 ; last entry?
+	brne NORELOAD
+	ldi idx, 0 ; rewind to the beginning of the table
+NORELOAD:
+	out OCR0AL, temp ; Shove the brightness into the PWM driver
 
-ldi idx, 0
-LOOP:
-    ldi ZH,high(SINETAB*2) + 0x40 ; This is start of Code in Tiny10 (0x4000)
-    ldi ZL, low (SINETAB*2) ; init Z-pointer to storage bytes
+; reset the watchdog timer to full value and sleep until it pops an interrupt
 
-add ZL, idx
-inc idx
+	; unfortunately we want to sleep 6k cycles to match the timing so sleep twice!
+	ldi temp, 0xD8		; write signature
+	out CCP, temp
+	; set watchdog in interrupt mode and 2k cycles
+	ldi temp, (0<<WDE)|(1<<WDIE)
+	out WDTCSR, temp
 
-ld temp, Z ; load next led brightness
-cpi temp, 0 ; last entry?
-brne NORELOAD
-ldi idx, 0 ; rewind to the beginning of the table
-NORELOAD:
+	wdr
+	sleep
+
+	ldi temp, 0xD8		; write signature
+	out CCP, temp
+	; set watchdog in interrupt mode and 4k cycles
+	ldi temp, (0<<WDE)|(1<<WDIE)|(1<<WDP0) 
+	out WDTCSR, temp
+
+	wdr
+	sleep
+
+
+	rjmp LOOP
 
-out OCR0AL, temp ; Shove the brightness into the PWM driver
 
-; delay!
-ldi delayms, DELAYTIME ; delay 10 ms
-DELAY:
-ldi delaycnt1, 0xFF
-DELAY1MS: ; this loop takes about 1ms (with 1 MHz clock)
-dec delaycnt1 ; 1 clock
-cpi delaycnt1, 0 ; 1 clock
-brne DELAY1MS ; 2 clocks (on avg)
-dec delayms
-cpi delayms, 0
-brne DELAY
+	; delay!
+;	ldi delayms, DELAYTIME ; delay 10 ms
+;DELAY:
+;	ldi delaycnt1, 0xFF
+;DELAY1MS: ; this loop takes about 1ms (with 1 MHz clock)
+;	dec delaycnt1 ; 1 clock
+;	cpi delaycnt1, 0 ; 1 clock
+;	brne DELAY1MS ; 2 clocks (on avg)
+;	dec delayms
+;	cpi delayms, 0
+;	brne DELAY
+;	rjmp LOOP
 
-rjmp LOOP
 
+; this is a do nothing interrupt handler for the watchdog interrupt
+WDT:
+	reti
 
 SINETAB:
 .db 1, 1, 2, 3, 5, 8, 11, 15, 20, 25, 30, 36, 43, 49, 56, 64, 72, 80, 88, 97, 105, 114, 123, 132, 141, 150, 158, 167, 175, 183, 191, 199, 206, 212, 219, 225, 230, 235, 240, 244, 247, 250, 252, 253, 254, 255, 254, 253, 252, 250, 247, 244, 240, 235, 230, 225, 219, 212, 206, 199, 191, 183, 175, 167, 158, 150, 141, 132, 123, 114, 105, 97, 88, 80, 72, 64, 56, 49, 43, 36, 30, 25, 20, 15, 11, 8, 5, 3, 2, 1, 0

Firmware/cuff.hex

@@ -1,12 +1,15 @@
 :020000020000FC
-:1000000000C0089A109A01EC0EBD01E80DBD00E099
-:1000100007BD10E0F0E4E8E3E10F13950081003044
-:1000200009F410E006BD32E32FEF2A952030E9F7FE
-:100030003A953030C9F7EECF0101020305080B0FE6
-:1000400014191E242B3138404850586169727B8442
-:100050008D969EA7AFB7BFC7CED4DBE1E6EBF0F439
-:10006000F7FAFCFDFEFFFEFDFCFAF7F4F0EBE6E12B
-:10007000DBD4CEC7BFB7AFA79E968D847B72696174
-:100080005850484038312B241E19140F0B08050313
-:040090000201000069
+:0200000008C036
+:100010002CC0089A109A0EE003B908ED0CBF08E056
+:1000200006BF01EC0EBD01E80DBD00E007BD08ED07
+:100030000CBF01E401BF01E00ABF789410E0F0E4D6
+:10004000ECE6E10F13950081003009F410E006BDE5
+:1000500008ED0CBF00E401BFA895889508ED0CBF22
+:1000600001E401BFA8958895EACF18950101020324
+:1000700005080B0F14191E242B31384048505861C5
+:1000800069727B848D969EA7AFB7BFC7CED4DBE1E4
+:10009000E6EBF0F4F7FAFCFDFEFFFEFDFCFAF7F4E8
+:1000A000F0EBE6E1DBD4CEC7BFB7AFA79E968D8459
+:1000B0007B7269615850484038312B241E19140F47
+:0800C0000B080503020100001A
 :00000001FF